High Quality Spherical Powders for Additive Manufacturing Processes Along With Methods of Their Formation

ABSTRACT

Methods for forming a high-quality powder from a feedstock powder of feedstock particles having irregular shapes are provided. The method includes exposing the feedstock powder to a plasma field to form a treated powder of treated particles having a more spherical shape than the feedstock particles. Prior to the plasma field exposure, the feedstock particles have an oxidized layer thereon as a result from previous exposure to water. After exposure to the plasma field, the treated particles are substantially free from an oxidized layer.

PRIORITY INFORMATION

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/551,981 titled “High Quality Spherical Powdersfor Additive Manufacturing Processes Along with Methods of TheirFormation” filed on Aug. 30, 2017, which is incorporated by referenceherein.

FIELD

The present invention generally relates to systems and methods forforming high quality spherical powders from a metallic powder feedstock.The high quality spherical powders are particularly suitable foradditively manufacturing an object or part.

BACKGROUND

Additive manufacturing processes generally involve the buildup of one ormore materials to make a net or near net shape (NNS) object, in contrastto subtractive manufacturing methods. Though “additive manufacturing” isan industry standard term, additive manufacturing encompasses variousmanufacturing and prototyping techniques known under a variety ofadditive manufacturing terms, including freeform fabrication, 3Dprinting, rapid prototyping/tooling, etc. Additive manufacturingtechniques are capable of fabricating complex components from a widevariety of materials. Generally, a freestanding object can be fabricatedfrom a computer aided design (CAD) model.

A particular type of additive manufacturing process uses an energy beam,for example, an electron beam or electromagnetic radiation such as alaser beam, to sinter or melt a powder material, creating a solidthree-dimensional object in which particles of the powder material arebonded together. Different material systems, for example, engineeringplastics, thermoplastic elastomers, metals, and ceramics are in use.Laser sintering or melting is also a notable additive manufacturingprocess for rapid fabrication of functional prototypes and tools.Applications include patterns for investment casting, metal molds forinjection molding and die casting, and molds and cores for sand casting.Fabrication of prototype objects to enhance communication and testing ofconcepts during the design cycle are other common usages of additivemanufacturing processes.

Laser sintering is a common industry term used to refer to producingthree-dimensional (3D) objects by using a laser beam to sinter or melt afine powder. More accurately, sintering entails fusing (agglomerating)particles of a powder at a temperature below the melting point of thepowder material, whereas melting entails fully melting particles of apowder to form a solid homogeneous mass. The physical processesassociated with laser sintering or laser melting include heat transferto a powder material and then either sintering or melting the powdermaterial.

In this process, the physical and chemical characteristics of the powdermaterial can impact the quality of the resulting object. That is, theproperties of a component built through additive manufacturing dependson the metal powder itself, with higher quality powders (e.g., denser,cleaner, and more spherical) behaving more predictably and thus resultsin better parts. As such, high quality powder material is required forcomponents formed from Additive Manufacturing techniques, particularlywhen used to manufacture components for gas turbine machinery and/ormedical implant or devices applications.

Powder making methods from a metal source mainly (as there are othertechniques like hydride/dihydride, ball milling, rotating electrode,plasma atomization etc.) include gas atomization and water atomization.Generally, gas atomization techniques result in particles with a morespherical and consistent shape, while water atomization techniquesresult in particles with an irregular shape. Additionally, due to thepresence of oxygen in water, an oxidized layer may form on the outsideof the particles formed by water atomization techniques. Currently,powders from gas atomization techniques are preferred for additivemanufacturing over powders formed from water atomization techniques,since powders formed from gas atomization techniques are more regular inshape (e.g., more spherical) and have a limited oxidized layer thereon.

However, powders formed from gas atomization are much more expensive toproduce than water atomization powders. Thus, the cost of the resultingcomponent formed from a gas atomized powder is high. As such, a needexists for reducing the cost of high quality powders for additivemanufacturing for higher adoption, while retaining control of thephysical and chemical characteristics of the powder material.

BRIEF DESCRIPTION

Aspects and advantages will be set forth in part in the followingdescription, or may be obvious from the description, or may be learnedthrough practice of the invention.

Methods are generally provided for forming a high-quality powder from afeedstock powder of feedstock particles having irregular shapes. In oneembodiment, the method includes exposing the feedstock powder to aplasma field to form a treated powder of treated particles having a morespherical shape than the feedstock particles. Prior to the plasma fieldexposure, the feedstock particles have an oxidized layer thereon as aresult from previous exposure to water. After exposure to the plasmafield, the treated particles are substantially free from an oxidizedlayer.

In one embodiment, the feedstock powder may be formed from wateratomization, mechanical crushing or grinding, gas atomization, and/orplasma atomization. For example, the oxidized layer on the feedstockparticles may be a result of exposure to water during a wateratomization process that formed the feedstock particles, or fromexposure to water vapor in the air during mechanical grinding.

To expose the feedstock powder to the plasma field, the method mayinclude introducing the feedstock powder into the plasma field such thatthe surface of the feedstock particles melts and/or evaporates to formthe more spherical shape.

In particular embodiments, the plasma field includes a reducingcomponent that reacts with the oxidized layer on the feedstockparticles, such as hydrogen, carbon monoxide, or a mixture thereof.

Through such a method, the treated particles may have an averageparticle size that is less than an average particle size of thefeedstock particles. For instance, the treated particles may have anaverage particle size that is about 10% to about 90% of the averageparticle size of the feedstock particles.

The feedstock particles may be formed from a metal material, such as apure metal, an iron alloy, an aluminum alloy, a nickel alloy, a chromealloy, a nickel-based superalloy, an iron-based superalloy, acobalt-based superalloy, or a mixture thereof. In one embodiment,particles an alloying element, such as carbon, may be mixed with thefeedstock particles within the plasma field.

In one embodiment, the method of forming a high-quality powder mayinclude: forming a feedstock powder via water atomization such that thefeedstock powder includes feedstock particles having irregular shapesand have an oxidized layer thereon; and thereafter, exposing thefeedstock powder to a plasma field to melt and/or evaporate the surfaceof the feedstock particles such that a treated powder of treatedparticles is formed having a more spherical shape than the feedstockparticles. The plasma field may include a reducing component (e.g.,hydrogen, carbon monoxide, or a mixture thereof) that reacts with theoxidized layer on the feedstock particles such that the treatedparticles are substantially free from an oxidized layer. In oneparticular embodiment, the treated particles have an average particlesize that is less than an average particle size of the feedstockparticles.

The resulting treated powders comprising the treated particles are alsogenerally provided herein, along with methods of additivelymanufacturing a component from such treated powders.

These and other features, aspects and advantages will become betterunderstood with reference to the following description and appendedclaims. The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and, together with the description, serve to explain certainprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appended Figs.,in which:

FIG. 1 shows an exemplary apparatus for plasma spheroidization of apowder material improving the properties of a powder material such thatthe improved powder material may be more suitable for additivemanufacturing techniques;

FIG. 2A is a scanning electron microscope (SEM) image of an exemplaryfeedstock powder according to Example;

FIG. 2B is a magnified SEM image of the exemplary feedstock powder ofFIG. 2A;

FIG. 3A is a SEM image of an exemplary spheroidized powder formed fromthe feedstock powder shown in FIGS. 2A and 2B prior to washing accordingto Example;

FIG. 3B is a magnified SEM image of the exemplary spheroidized powder ofFIG. 3A;

FIG. 4A is a SEM image of the exemplary spheroidized powder shown inFIGS. 3A and 3B after washing according to the Example; and

FIG. 4B is a magnified SEM image of the exemplary washed, spheroidizedpowder of FIG. 4A.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

As used herein, the terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terms “upstream” and “downstream” refer to the relative directionwith respect to fluid flow in a fluid pathway. For example, “upstream”refers to the direction from which the fluid flows, and “downstream”refers to the direction to which the fluid flows.

Methods are generally provided for creating higher quality powdermaterials (i.e., a treated powder) from a lower-quality powder source(i.e., a feedstock powder), along with apparatus to perform such methodsand the resulting particles. In one embodiment, a powder formed fromwater atomization techniques and having irregular shapes (such as formedfrom water atomization techniques) is transformed into a higher qualitypowder. In one embodiment, treated particles of the treated powder mayhave a more spherical shape than the feedstock particles of thefeedstock powder, which may be irregular, non-spherical in shape.Additionally, any oxidation layer present on the feedstock powder may beremoved (e.g., through chemical reduction). In one embodiment, thetreated powder may be substantially free from any oxidation layer on itssurface. As used herein, the term “substantially free” means no morethan an insignificant trace amount present and encompasses completelyfree (e.g., 0 molar % up to 0.01 molar %).

In one embodiment, the treated powder is subjected to (e.g., exposed to)plasma spheroidization to produce the high quality powder. Referring toFIG. 1, a diagram of a plasma spheroidization apparatus 10 is generallyshown. The feedstock powder 12 (composed of a plurality of feedstockparticles 13) is generally introduced into a plasma chamber 14, alongwith a working gas 16 (also referred to as the plasma gas, no matter itsstate of matter). A plasma field 18 may be formed within the plasmachamber 14 through heating to a temperature sufficient to convert theplasma gas 16 from its gaseous state into its plasma state. For example,heating elements 20 may be included within the plasma chamber 14, suchas an induction coil.

As stated above, the feedstock particles 13 may have an irregular shape(e.g., non-spherical) when introduced into the plasma chamber 14. Incertain embodiments, the feedstock particles 13 have a maximum size ofabout 150 micrometers (μm). For example, the feedstock particles 13 mayhave an average size of about 10 μm to about 150 μm (e.g., about 50 μmto about 100 μm).

Generally, the feedstock powder 12 may be any metal material. In oneembodiment, the metal material may include, but is not limited to, puremetals, iron alloys, aluminum alloys, nickel alloys, chrome alloys,nickel-based superalloys, cobalt-based superalloys, iron-basedsuperalloys, or mixtures thereof. In particular embodiments, alloyingelements may be mixed with the feedstock powder 12 prior to or duringexposure to the plasma gas 16. As such, the chemical composition of theresulting treated powder may be controlled. For example, in oneparticular embodiment, carbon particles may be mixed with the feedstockparticles within the plasma field.

As the feedstock powder 12 is passed through the plasma field 18 thatincludes the plasma gas 16 in its plasma state, the surface of thefeedstock particles 13 melts or evaporates within a melting zone 22 thatincludes the plasma field 18. However, without wishing to be bound byany particular theory, it is believed that the feedstock particles 13 donot entirely melt and/or evaporate, but rather that the surfaces of thefeedstock particles 13 are melted/softened so as to reshape into a moreregular shape (e.g., more spherical) while having a smaller size. Thus,at least a portion of the surface of the feedstock particles 13 aremelted/softened within the melting zone 22.

In one embodiment, the working gas 16 (i.e., the plasma gas) includes areducing gas, such as hydrogen, carbon monoxide, or a mixture thereof.The reducing gas may react with any oxide layer on the surface of thefeedstock particles 13, which may be in the form of chromium oxide, ironoxide, etc. Such a reducing gas may react with the oxide to remove itfrom the surface such that the resulting treated powder 24 (in the formof a plurality of the resulting treated particles 25) are substantiallyfree from any oxide layer thereon. Thus, in one particular embodiment,the reducing component reduces any oxide layer on the surface of thefeedstock particles such that the resulting treated particles aresubstantially free from any oxide layer thereon.

Through this plasma spheroidization process, the size of the feedstockparticles 13 may be decreased such that the resulting treated particles25 have an average particle size that is less than an average particlesize of the feedstock particles 13. In one embodiment, the resultingtreated particles 25 have an average particle size that is about 10% toabout 90% of the average particle size of the feedstock particles 13. Incertain embodiments, the treated particles 25 have a maximum size ofabout 150 μm (e.g., an average size of about 10 μm to about 150 μm). Inparticular embodiments, the treated particles 25 have a maximum size ofabout 50 μm (e.g., an average size of about 10 μm to about 50 μm).

Such a technique can be used to recondition powders as well.

As stated, the plasma spheroidization of the feedstock powder 12improves the properties of the feedstock powders 12 such that theimproved powder material (i.e., the treated powder 24) may be moresuitable for additive manufacturing techniques. As used herein, theterms “additively manufactured” or “additive manufacturing techniques orprocesses” refer generally to manufacturing processes wherein successivelayers of material(s) are provided on each other to “build-up,”layer-by-layer, a three-dimensional component. The successive layersgenerally fuse together to form a monolithic component which may have avariety of integral sub-components. Although additive manufacturingtechnology is described herein as enabling fabrication of complexobjects by building objects point-by-point, layer-by-layer, typically ina vertical direction, other methods of fabrication are possible andwithin the scope of the present subject matter. For example, althoughthe discussion herein refers to the addition of material to formsuccessive layers, one skilled in the art will appreciate that themethods and structures disclosed herein may be practiced with anyadditive manufacturing technique or manufacturing technology. Forexample, embodiments of the present invention may use layer-additiveprocesses, layer-subtractive processes, or hybrid processes.

Suitable additive manufacturing techniques in accordance with thepresent disclosure include, for example, Fused Deposition Modeling(FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjets,laser jets, and binder jets, Sterolithography (SLA), Direct SelectiveLaser Sintering (DSLS), Electron Beam Sintering (EBS), Electron BeamMelting (EBM), Laser Engineered Net Shaping (LENS), Laser Net ShapeManufacturing (LNSM), Direct Metal Deposition (DMD), Digital LightProcessing (DLP), Direct Selective Laser Melting (DSLM), Selective LaserMelting (SLM), Direct Metal Laser Melting (DMLM), and other knownprocesses.

The additive manufacturing processes described herein may be used forforming components using any suitable material. For example, thematerial may be plastic, metal, concrete, ceramic, polymer, epoxy,photopolymer resin, or any other suitable material that may be in solid,liquid, powder, sheet material, wire, or any other suitable form orcombinations thereof. More specifically, according to exemplaryembodiments of the present subject matter, the additively manufacturedcomponents described herein may be formed in part, in whole, or in somecombination of materials including but not limited to pure metals, ironalloys, aluminum alloys, nickel alloys, chrome alloys, and nickel-based,iron-based, or cobalt-based superalloys (e.g., those available under thename Inconel® available from Special Metals Corporation). Thesematerials are examples of materials suitable for use in the additivemanufacturing processes described herein, and may be generally referredto as “additive materials.”

In addition, one skilled in the art will appreciate that a variety ofmaterials and methods for bonding those materials may be used and arecontemplated as within the scope of the present disclosure. As usedherein, references to “fusing” may refer to any suitable process forcreating a bonded layer of any of the above materials. For example, ifan object is made from polymer, fusing may refer to creating a thermosetbond between polymer materials. If the object is epoxy, the bond may beformed by a crosslinking process. If the material is ceramic, the bondmay be formed by a sintering process. If the material is powdered metal,the bond may be formed by a melting or sintering process. One skilled inthe art will appreciate that other methods of fusing materials to make acomponent by additive manufacturing are possible, and the presentlydisclosed subject matter may be practiced with those methods.

In addition, the additive manufacturing process disclosed herein allowsa single component to be formed from multiple materials. Thus, thecomponents described herein may be formed from any suitable mixtures ofthe above materials. For example, a component may include multiplelayers, segments, or parts that are formed using different materials,processes, and/or on different additive manufacturing machines. In thismanner, components may be constructed which have different materials andmaterial properties for meeting the demands of any particularapplication. In addition, although the components described herein areconstructed entirely by additive manufacturing processes, it should beappreciated that in alternate embodiments, all or a portion of thesecomponents may be formed via casting, machining, and/or any othersuitable manufacturing process. Indeed, any suitable combination ofmaterials and manufacturing methods may be used to form thesecomponents.

An exemplary additive manufacturing process will now be described.Additive manufacturing processes fabricate components usingthree-dimensional (3D) information, for example a three-dimensionalcomputer model, of the component. Accordingly, a three-dimensionaldesign model of the component may be defined prior to manufacturing. Inthis regard, a model or prototype of the component may be scanned todetermine the three-dimensional information of the component. As anotherexample, a model of the component may be constructed using a suitablecomputer aided design (CAD) program to define the three-dimensionaldesign model of the component.

The design model may include 3D numeric coordinates of the entireconfiguration of the component including both external and internalsurfaces of the component. For example, the design model may define thebody, the surface, and/or internal passageways such as openings, supportstructures, etc. In one exemplary embodiment, the three-dimensionaldesign model is converted into a plurality of slices or segments, e.g.,along a central (e.g., vertical) axis of the component or any othersuitable axis. Each slice may define a thin cross section of thecomponent for a predetermined height of the slice. The successivecross-sectional slices together form the 3D component. The component isthen “built-up” slice-by-slice, or layer-by-layer, until finished.

In this manner, the components described herein may be fabricated usingthe additive process, or more specifically each layer is successivelyformed, e.g., by fusing or polymerizing a plastic using laser energy orheat or by sintering or melting metal powder. For example, a particulartype of additive manufacturing process may use an energy beam, forexample, an electron beam or electromagnetic radiation such as a laserbeam, to sinter or melt a powder material. Any suitable laser and laserparameters may be used, including considerations with respect to power,laser beam spot size, and scanning velocity. The build material may beformed by any suitable powder or material selected for enhancedstrength, durability, and useful life, particularly at hightemperatures.

Each successive layer may be, for example, between about 10 μm and 200μm, although the thickness may be selected based on any number ofparameters and may be any suitable size according to alternativeembodiments. Therefore, utilizing the additive formation methodsdescribed above, the components described herein may have cross sectionsas thin as one thickness of an associated powder layer, e.g., 10 μm,utilized during the additive formation process.

In addition, utilizing an additive process, the surface finish andfeatures of the components may vary as need depending on theapplication. For example, the surface finish may be adjusted (e.g., madesmoother or rougher) by selecting appropriate laser scan parameters(e.g., laser power, scan speed, laser focal spot size, etc.) during theadditive process, especially in the periphery of a cross-sectional layerwhich corresponds to the part surface. For example, a rougher finish maybe achieved by increasing laser scan speed or decreasing the size of themelt pool formed, and a smoother finish may be achieved by decreasinglaser scan speed or increasing the size of the melt pool formed. Thescanning pattern and/or laser power can also be changed to change thesurface finish in a selected area.

Notably, in exemplary embodiments, several features of the componentsdescribed herein were previously not possible due to manufacturingrestraints. However, the present inventors have advantageously utilizedcurrent advances in additive manufacturing techniques to developexemplary embodiments of such components generally in accordance withthe present disclosure. While the present disclosure is not limited tothe use of additive manufacturing to form these components generally,additive manufacturing does provide a variety of manufacturingadvantages, including ease of manufacturing, reduced cost, greateraccuracy, etc.

In this regard, utilizing additive manufacturing methods, evenmulti-part components may be formed as a single piece of continuousmetal, and may thus include fewer sub-components and/or joints comparedto prior designs. The integral formation of these multi-part componentsthrough additive manufacturing may advantageously improve the overallassembly process. For example, the integral formation reduces the numberof separate parts that must be assembled, thus reducing associated timeand overall assembly costs. Additionally, existing issues with, forexample, leakage, joint quality between separate parts, and overallperformance may advantageously be reduced.

Also, the additive manufacturing methods described above enable muchmore complex and intricate shapes and contours of the componentsdescribed herein. For example, such components may include thinadditively manufactured layers and unique fluid passageways withintegral mounting features. In addition, the additive manufacturingprocess enables the manufacture of a single component having differentmaterials such that different portions of the component may exhibitdifferent performance characteristics. The successive, additive natureof the manufacturing process enables the construction of these novelfeatures. As a result, the components described herein may exhibitimproved functionality and reliability.

EXAMPLES

As an example, water atomized powder was purchased from under theirdesignation 316 powder, which had the sizing of −325 mesh/15 microns.This water atomized powder is an iron-based alloy. The water atomizedpowder was found to have an apparent density of 2.75 (g/cm³) with anoxygen content of 0.164% (by wt.), nitrogen content of 0.047% (wt %),and hydrogen content of 0.001% (by wt. %). The water atomized powder wasfound to have the particle size distribution shown in Table 1 prior toany treatment performed.

TABLE 1 Volume Statistics (Arithmetic) Calculations from 0.375 μm to2000 μm <10% <25% <50% <75% <90% 15.98 μm 24.72 μm 34.62 μm 45.18 μm55.68 μm Volume: 100% SD: 15.95 μm Mean: 35.65 μm Variance: 254.4 μm²Median: 34.62 μm C.V.: 44.7% Mean/Median Ratio: 1.030 Skewness: 0.588right skewed Mode: 37.97 μm Kurtosis: 0.773 Leptokurtic

FIGS. 2A and 2B show SEM images of the water atomized powder prior toany treatment performed. As shown, the water atomized powder includesparticles of varying size and shape.

Then, the water atomized powder was spheroidized using argon as aprimary gas, with hydrogen as a secondary gas. Other experiments werealso performed using helium and nitrogen as a secondary gas, with argonbeing the primary gas. It was found that the spheroidization resulted ina more uniform size and shape of the particles in the powder.

FIGS. 3A and 3B shown images of the spheroidized powder afterspheroidized using argon as a primary gas and hydrogen as a secondarygas.

Then, the spheroidized powder was washed using an industrial washingunit. FIGS. 4A and 4B show images of the spheroidized powder. As seen,relatively clean and uniform particles make up the powder following thisspheroidization and washing process.

The spheroidized powder was found to have an oxygen content of 0.057%(wt %), nitrogen content of 0.009% (wt %), and hydrogen content of0.0007% (wt %). Thus, the spheroidized powder had significantly reducedcontents of oxygen, nitrogen, and hydrogen.

Table 2 shows the particle size distribution after spheroidization andwashing.

TABLE 2 Volume Statistics (Arithmetic) Calculations from 0.375 μm to2000 μm <10% <25% <50% <75% <90% 19.55 μm 24.86 μm 30.48 μm 35.97 μm40.80 μm Volume: 100% SD: 8.014 μm Mean: 30.30 μm Variance: 64.23 μm²Median: 30.48 μm C.V.: 26.4% Mean/Median Ratio: 0.994 Skewness: −0.085left skewed Mode: 31.51 μm Kurtosis: −0.347 Platykurtic

In conclusion, spheroidization of water atomized powder was successfuland overcame both of the major issues of irregular shape and high oxygencontent.

This written description uses exemplary embodiments to disclose theinvention, including the best mode, and also to enable any personskilled in the art to practice the invention, including making and usingany devices or systems and performing any incorporated methods. Thepatentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those skilled in the art. Suchother examples are intended to be within the scope of the claims if theyinclude structural elements that do not differ from the literal languageof the claims, or if they include equivalent structural elements withinsubstantial differences from the literal languages of the claims.

What is claimed is:
 1. A method of forming a high-quality powder from a feedstock powder of feedstock particles having irregular shapes, the method comprising: exposing the feedstock powder to a plasma field to form a treated powder of treated particles having a more spherical shape than the feedstock particles, wherein the feedstock particles have an oxidized layer thereon as a result from previous exposure to water, and wherein the treated particles are substantially free from an oxidized layer.
 2. The method of claim 1, wherein the feedstock powder is formed from water atomization, mechanical crushing or grinding, gas atomization, and/or plasma atomization.
 3. The method of claim 1, wherein the oxidized layer on the feedstock particles is a result of exposure to water during a water atomization process that formed the feedstock particles.
 4. The method of claim 1, wherein exposing the feedstock powder to the plasma field comprises: introducing the feedstock powder into the plasma field such that at least a portion the surface of the feedstock particles melts or evaporates to form the more spherical shape.
 5. The method of claim 4, wherein the plasma field comprises a reducing component that reacts with the oxidized layer on the feedstock particles.
 6. The method of claim 5, wherein the reducing component comprises hydrogen, carbon monoxide, or a mixture thereof.
 7. The method of claim 1, wherein the feedstock particles have a maximum size of about 150 μm.
 8. The method of claim 7, wherein the feedstock particles have an average size of about 10 μm to about 150 μm.
 9. The method of claim 8, wherein the feedstock particles have an average size of about 50 μm to about 100 μm.
 10. The method of claim 1, wherein the treated particles have an average particle size that is less than an average particle size of the feedstock particles.
 11. The method of claim 1, wherein the treated particles have an average particle size that is about 10% to about 90% of the average particle size of the feedstock particles.
 12. The method of claim 1, wherein the feedstock particles comprise a metal material.
 13. The method of claim 12, wherein the metal material comprises a pure metal, an iron alloy, an aluminum alloy, a nickel alloy, a chrome alloy, a nickel-based superalloy, an iron-based superalloy, a cobalt-based superalloy, or a mixture thereof.
 14. The method of claim 1, wherein carbon particles are mixed with the feedstock particles within the plasma field.
 15. The treated powder comprising the treated particles formed from the method of claim
 1. 16. A method of additively manufacturing a component from the treated powder of claim
 15. 17. A method of forming a high-quality powder, the method comprising: forming a feedstock powder via water atomization, wherein the feedstock powder includes feedstock particles having irregular shapes, and wherein the feedstock particles have an oxidized layer thereon; thereafter, exposing the feedstock powder to a plasma field to melt or evaporate at least a portion of the surface of the feedstock particles such that a treated powder of treated particles is formed having a more spherical shape than the feedstock particles, wherein the plasma field comprises a reducing component that reacts with the oxidized layer on the feedstock particles such that the treated particles are substantially free from an oxidized layer.
 18. The method of claim 17, wherein the reducing component comprises hydrogen, carbon monoxide, or a mixture thereof.
 19. The method of claim 17, wherein the treated particles have an average particle size that is less than an average particle size of the feedstock particles.
 20. The method of claim 1, wherein the feedstock particles comprise a metal material, and wherein carbon particles are mixed with the feedstock particles within the plasma field. 